This research is dedicated to the development of a new method of time-resolved, 3D velocity imaging with magnetic resonance, providing a valuable clinically applicable, non-invasive tool for studying hemodynamics. A fast, 3D acquisition scheme will reduce some of the flow artifacts encountered in 2D imaging, improve the signal to noise ratio, and provide a more complete picture of complex flow. Studies of complex flow are important for answering basic questions concerning the progression of arteriosclerosis, the design of cardio-vascular surgeries, and the interaction of blood flow patterns and anatomic structures. This project will focus on the flow patterns in the heart as this is the most challenging location for successfully obtaining time-resolved, 3D velocity information. Three different data acquisition schemes will be investigated. These schemes differ in the way they sample k-space and include traditional Cartesian sampling, echo planar techniques, and spiral acquisitions. The optimized sequences will be validated with in vitro flow models and compared to the known flow conditions, computational flow dynamic studies, and to other flow measurement methods available in vitro. At the end of this study, a method will be ready for application in in vivo studies, where they can be used to obtain clinically relevant information in patients with heart or vessel disease and to answer basic questions about how anatomy and structure affect blood now in health and disease.